United Kingdom declares war on France, beginning the Napoleonic Wars

Background. The Treaty of Amiens was signed at Amiens on 25 March 1802 by Joseph Bonaparte and Charles Cornwallis as a "Definitive Treaty of Peace". The consequent peace lasted only one year, ending on 18 May 1803, and was the only period of general peace in Europe between 1793 and 1814. Bonaparte protested continuing British occupations and in January 1803 published a report by Horace Sebastiani observing how easily France might capture Egypt, alarming most European powers. In February 1803 he threatened war against Lord Whitworth if Malta was not evacuated.

Declaration of War. Britain ended the uneasy truce by declaring war on France in May 1803. Historians argue this decision stemmed from economic motives and national anxieties about Napoleon's intentions. The declaration marked the start of the first stage of the Napoleonic Wars, a global series of conflicts against French domination.

Immediate Actions. Before the official declaration, the Royal Navy captured French and Dutch merchant ships in Britain on 17 May 1803, seizing commodities and taking crews as prisoners. The Addington ministry had already ordered military preparations in March 1803 due to concerns about French retaliation for treaty breaches.